The desire to alter the color of human hair is not a facet of modern times. Since the days of the Roman Empire the color of human hair has been routinely altered to accommodate the changes of fashion and style. However the attainment of precise initial colors which are retained by the hair for a desirable period has remained a more elusive goal. The difficulties in the development of hair coloring compositions which can deliver precise long-lasting colors are in part due to the inherent structure of the hair itself and in part due to the necessary conditions of effective hair coloration processes.
Over the years significant effort has been directed towards the elimination of many of the problems associated with the dyeing of human hair. Various approaches to hair dyeing have been developed, these include, direct action dyes, natural dyes, metallic dyes and oxidative dyes.
To color human or animal hair using oxidative dye technology the hair is generally treated with a mixture of oxidative hair coloring agents and an oxidising agent.
Oxidative hair coloring agents and oxidising agents can be used to deliver a variety of hair colors to the hair. However substantial improvement is needed in the area of application characteristics of coloring compositions, such as, time to prepare the coloring composition, mess on application, waste of product not used, waste of packaging (from use of multiple component systems), storage stability (of the coloring composition once mixed), and the ability to re-use the mixed coloring composition. Re-use, of a coloring composition, as defined herein, means, correction of mistakes, touching up or root coverage, and future re-coloring of the hair with the same product as well as color and/or strand tests on small areas of hair.
In addition to the improvements in application charateristics as detailed hereinbefore, substantial improvement is needed in the area of coloring characteristics such as, color saturation, color development, precise initial color consistency, improved wash fastness, improved hair condition and levels of hair damage.
Conventional oxidative hair dyeing compositions generally comprise at least two separately packaged components. Typically, these components include oxidising agent (at low pH), such as hydrogen peroxide, and dyeing material (at high pH), such as oxidative hair coloring agents. In order to facilitate the hair dyeing process these separately packaged components are generally admixed just prior to application of the coloring composition to the hair. After mixing, such, high pH, compositions tend to degrade which can lead to reduced or impaired coloring ability. High pH hair coloring compositions are typically used soon after admixing. In general, any excess, admixed, coloring composition is disposed of after application of the required amount to the hair. Furthermore, such conventional coloring compositions, once mixed, cannot be stored and/or re-used, as the activated oxidative dyeing system rapidly deteriorates over time. Thus, it would be desirable to develop an oxidative hair coloring composition which comprises both oxidising agent and oxidative coloring agents which is storage stable and/or re-useable.
As detailed hereinbefore conventional oxidative hair dyeing compositions generally comprise at least two separately packaged components. In addition to the time required to effectively mix these components, the mixing process itself can be both messy and wasteful as well as causing added inconvenience to the user. Thus, it would be desirable to develop a convenient and easy-to-use method for the delivery of oxidative hair coloring compositions to the hair which does not require mixing of the oxidising and coloring components.
It would also be desirable to develop a hair coloring composition comprising an oxidising agent and an oxidative hair coloring agent which can be stored as separately packaged, stable, low pH, components which, on mixing, provides a shelf-stable, low pH mixture which is suitable for direct application to the hair. This low pH mixture could be stored and re-used. This would allow the consumer to correct mistakes, touch up roots or re-apply product,without re-purchase.
It has been found that, at low pH, mixtures of oxidising agents and oxidative hair coloring agents, can be packaged together, in a single pack, and are storage stable and re-usable. It has also been found that such low pH mixtures of oxidising agent and oxidative hair coloring agents provide improved initial hair coloring attributes versus conventional, high pH, compositions. It has also been found that, low pH mixtures of oxidising agent and oxidative hair coloring agents, which have been stored at room temperature, provide improved color development potential versus conventional coloring compositions.
It has also been found that, at low pH, both the oxidising agent and oxidative hair coloring agents are stable over time, and can be stored as such.
It is an object of the present invention to provide, low pH hair coloring compositions comprising both oxidising agents and oxidative hair coloring agent which are singly packaged, which are fast acting, simple to use, storage stable, and which are re-usable.
It has been found that the above objects can be met by the low pH, storage stable, re-usable hair coloring compositions according to the present invention.
All percentages are by weight of the final compositions in the form intended to be used unless specified otherwise.